Manual leaf area measurement on individual sugar beet plants taking plant density and irrigation into account

For sugar beet growth models, knowledge of the development of the photosynthetically active leaf apparatus with its up to more than 50 individual leaves per beet plant as a source of assimilate production is very important. Because the measurement using leaf area index (LAI) meters from above allows only a limited measurement and does not cover the total leaf area of all existing individual leaves, it is necessary to carry out manually leaf area measurements for individual sugar beet plants over the whole growth period without destroying the leaves. For this reason, a special measuring methodology was developed and applied. On the experimental fields of the Research Centre for Soil Fertility Müncheberg (FZB Müncheberg) (location: 52°01`N, 14°07`E, 14°07`Eastern latitude; location type: D 2a; soil type: sandy-loamy soil; German soil quality index: 26; average (1951-1981) annual precipitation: 544 mm; average (1951-1981) annual temperature: 8.2°C) leaf area measurements were carried out in different experiments with sugar beets between 1979 and 1982. In each experimental variant, the leaf areas of 8 individual plants were measured between emergence and harvesting of the sugar beet at intervals of approximately 7 days. Between end of May and mid-October usually about 20 measurements were realized. The leaf area is given in cm2 per sugar beet plant. Experiments with different crop densities (60,000, 80,000 and 100,000 sugar beet plants per hectare) as well as without and with irrigation (based on pen evaporation or based on model-added irrigation scheduling system EDV-BB) were taken into account.